As far as I know, there is no equivalent in Canada (for noise). The EPA equivalent would probably be the Ministry of the Environment. They deal mostly with pollution.
I live in a similar situation, and I can sympathise... I have a similar problem of noisy (not to mention rude) neighbours.
Although the level of noise here is not so bad (earplugs work in my case), I am sort of lucky in that the Quebec laws allow you not to pay your rent to the landlord (but instead deposit it with the Régie du logement, who keeps it until the landlord solves the problem) in cases such as this, whenever I threaten them that I am not going to pay the rent, they actually do something.
I suggest you read carefully through the Ontario rental laws, I am pretty sure that there has to be some clause that protects the tenants, and there should be something that you can use to your advantage. Also sending a registered letter of complaint directly to whoever owns the building might help you there.
I only hope that years of Tory government in Ontario haven't destroyed every trace of civil rights...
In any case good luck and keep us posted.
